Protective arrangement for use with apparatus or machines having rotating parts



2,999,667 PROTECTIVE ARRANGEMENT FOR USE WITH APPARATUS Sept. 12, 1961F. w. w. MoRLx-:Y

OR MACHINES HAVING ROTATING PARTS l 3 Sheets-Sheet 1 Filed Sept. l2,1957 F. W. W. MORLEY Sept. 12, 1961 PROTECTIVE ARRANGEMENT FOR USE WITHAPPARATUS OR MACHINES HAVING ROTATING -PARTS 3 Sheets-Sheet 2 FiledSept. l2, 1957 SR l.

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Sept 12, 1961 F. W. w. MORLEY 2,999,667

PROTECTIVE ARRANGEMENT PoR USE wITR APPARATUS 0R MACHINES HAVINGRoTATING PARTS Filed Sept. 12, 1957 5 Sheets-Sheet 3 United States Thisinvention relates to protective arrangements for use Iwith rotatingparts.

The breaking-off of some fragment of a part which is rotating at highspeed is in eiiect the release of a highenergy projectile, and seriousconsequences may result, as vfor example, in the case of the fracture ofa turbine blade or part of a turbine disc from the rotor of an aircraftgas-turbine engine. It is an object of the present invention to reducethe risk of serious damage resulting from such breakage.

According to the present invention there is provided for use with arotating part from breaking of which protection is desired, a protectivearrangement comprising a web fabricated from closely woven or braidedWire, strip or the like, said web being adapted to be supported bystationary structure to surround the rotating part so -as to interceptfragments breaking off the rotating part. The protective arrangement maycomprise more than one layer of such a web, the layers beingconveniently formed frolm one continuous web -wound into an open-centredco1 According to a preferred form of this invention, a protectivearrangement for use with an apparatus or machine having a rotating partfrom breaking of which protection is desired, for example for use with agas turbine, comprises a web constituted by a flattened tube of closelyinterwoven wires which extend from end to end of the tube, the web beingwound into an opencentred coil of a plurality of layers which in usesurrounds the rotating part of the apparatus or machine in spacedrelation thereto, and the web being adapted to be supported fromstationary structure of the apparatus or machine.

According to a preferred feature of this invention, the protectivearrangement may also comprise a sheet metal tubular liner inside thewound web to assist distribution of loads resulting from impact of abroken fragment.

In one arrangement employing this latter feature of the invention, theliner is spaced radially away from the web and carries on its externalsurface a series of circumferentially-extending overlapping plates, andthe liner has secured to it a series of axially-extending bars havinganges which are spaced from the liner and provide Ieach a hook locationfor one of the overlapping plates, the plates having each an inturnededge engaging the corresponding ilange. One of the said plates may havesecured to it means for locating one end of the web. For instance saidmeans may comprise a anged bar and the web may have at its end a hookedfitting co-operating with the flange of the bar. The web is preferablyaccommodated within a casing of which the liner may form an inner wall.

This invention also comprises the combination with a gas turbine or thelike, of a protective arrangement as above set forth, the protectivearrangement surrounding the turbine casing in spaced relation thereto.The protective arrangement may if desired form a wall of a cooling airjacket around the turbine.

A construction of gas-turbine incorporating a form of protectivearrangement of this invention will now be described with reference tothe accompanying drawings, in which:

arent G ICC FIGURE 1 is a diagrammatic section through the turbine andprotective arrangement;

FIGURE 2 is a corresponding view to a larger scale of the protectivearrangement;

FIGURE 3 is a section on the line 3-3 of FIGURE 2 and shows the lineofsection 2-2 of FIGURE 2;

FIGURE 4 illustrates a detail of one end of the web, and

FIGURE 5 is a view similar to FIGURE 3 but shows the use of layers ofsheet metal.

The gas turbine illustrated in .FIGURE 1 comprises a main casing 10enclosing a rotor. The rotor comprises three turbine discs .11 eachcarrying a ring of turbine blades 12. The turbine also comprises a ringof nozzle guide vanes 14 at the entry to each ring of turbine bladesi12, the vanes 14 being mounted on the casing 19.

It will be appreciated that in event of breakage of a rotor blade 12 orof failure of a rotor disc 11 in operation of the turbine, considerabledamage may be caused due to fragments of the blade or disc being thrownoit at high speed and passing through the casing 10.

There is therefore provided a protective arrangement 15 surrounding theturbine in spaced relation to the casing 19 to intercept such fragments.

vThe protective arrangement illustrated in FIGURES 2 to 4 comprisesprimarily a long web 16 of interwoven wires which are continuous fromone end of the web to the other, the web 16 surrounding the turbine in acoil of a number of layers 16a say three to six layers (three suchlayers are shown).

In the form illustrated, the wires are vbraided intoy a tube which isthen ilattened, the flattened tube having a width say 12 inches,sufhcient to extend axially from one end to the other of the turbine anda length Sullicient to provide the desired number of layers. Each layerthus comprises two thicknesses of interwoven wires. The course of a wirein the attened tube is indicated at 16b each wire passing unbrokenlyaround the engine a number of times and also between the lengthwiseedges of the web a large number of times. Thus the web 16 is capable ofabsorbing large amounts of energy by virtue of its capacity fordeformation under strain. Also the reaction force involved in stopping apiece which breaks olf the rotor is spread evenly over a large portionof the engine frame. The wire from which the web is made may be, forexample, steel lhaving an ultimate tensile stress of tons per squareinch, or drawn aluminum.

The web |16 may be supported by being enclosed in coil form in a casing.The casing `comprises an inner tubular, sheet metal liner 17 to theexternal surface of which are welded at circu-mferentially spacedpositions a series of axially-extending bars 18 which have flanges 18aspaced radially from the liner 17. The liner 17 has Welded to it at oneof its axially-spaced edges a ring 19 with a thickenedaxially-projecting edge 19a, and a flanged end |wall 20, and has weldedto its opposite edge a ring 21 with a bolting flange 21a which providesthe other end wall of the casing. The casing also comprises a detachableouter wall 22 one end of which slidingly engages below a ilange 29a onthe end Iwall 29 and the opposite edge of which carries a ring 23 with abolting flange 23a which bears against the bolting flange 21a. Removalof the outer wall 22 exposes the web 16.

The bars 18 provide hook locations for a series 'of overlapping,circumferentially-extending plates 24 each of which has at one edge aninturned ange 24a engaging below the flange 18a of one of the bars 18.

The main portions of the plates are thus held in radially-spacedrelation to the liner 17.

The liner 17 and the plates 24 assist to` prevent a sha1-ply pointedbroken portion penetrating between and 3 shearing through the wires ofthe web 16 at the point of impact, and to assist in spreading of theload.

The assembly may be further reinforced and distribution of the loadresulting from impact of the broken piece lfurther improved byintercalating sheets of metal between the layers of the web.

One of the plates 24 has Welded to its outer surface an axiallyextending bar 25 having an edge flange 25a spaced away from the plate.This bar 25 serves lto locate one end of the web 16 which is `fitted, asby brazing and stapling, with a co-operating hook fitting 26 extendingacross the Whole Width of the web 16. The opposite end of the web 16 islocated with a limi-ted circumierential freedom by being provided with afitting 27 with a channel 27a in its outer surface extending across thewidth of the web, and the channel is engaged by a rib 28a on a bar 28welded to the outer wall 22 of the casing.

In the illustrated construction, the protective arrangement is supported`from stationary structure of the turbine to form part olf an air jacketsurrounding the casing 10 so as to odset in part the increase in weightof the engine due to the provision of the protective arl rangement. Theair jacket comprises a vwall 30* spaced from the casing 10 and having atits downstream end a radi-al flange 31 which has a bead 32 `at its outeredge. The thickened edge 19a of the ring 19 slidingly engages anaxially-facing channel in the bead 32.

The air jacket also comprises an fair outlet manifold structure 33including an air outlet connection 33a which structure is spaced axiallyfrom the wall 30 by a distance approximatley equal to the axial lengthof the protective arrangement and which is provided with a boltingflange 34 which abuts the bolting flange 28a. Retaining bolts 35 passthrough the flanges 34, 23a and thread into the flange 21a. Theprotective arrangement 15 is thus held in spaced relation to the casing10 and forms part of the Wall of the cooling air passage 36 leading tothe manifold structure 33. The spacing of theliner =17 and casing 10 issuch that a piece breaking olf the rotor 11, 12 shall have suliicientspace to avoid its being punched through the protective arrangement 15by the remainder of the turbine disc. The mounting of the protectivearrangement 15 also allows for diametral expansion and contraction ofthe turbine casing 10.

In one example the liner 17 is 0.1 inch thick steel and the web 16 ismade of braided .030 inch thick steel Wire. The reinforcing plates 24are .030 inch thick steel sheets, and similar sheets 40 may beintercalated between the layers of the web, as shown in FIGURE 5. Thediametral dimensions of the protective arrangement 15 are such that aminimum radial gap of 1 inch is left between the arrangement 15 and theturbine casing.

I claim:

1. A protective device for use with apparatus having a rotating part andstationary structure, said device cornprising a tubular liner memberwhich in use of the device surrounds the rotating part, -a plurality oflayers of interwoven wire encircling said liner member, means supportingsaid layers of interwoven wire in radially spaced relation to said linermember, an outer tubular wall member surrounding said plurality oflayers of interwoven wire, said outer tubular wall member being securedto said liner member, and means for securing the device to thestationary structure of the apparatus.

2. A protective device Kfor use with apparatus having a rotating partand stationary structure, said device comprising a continuous web ofinterwoven wire wound into an open-centered coil having a plurality oflayers, a tubular liner member internally of said coil, means supportingsaid coil in radially spaced relation to said. liner member, an outertubular wall member surrounding said coil, the outer tubular wall memberbeing secured to the liner member, and means for securing the device tothe stationary structure of the apparatus.

3. A protective device according to claim 2, wherein the continuous webis constituted by a dattened tube of closely interwoven wires whichextend from end to end of the flattened tube. s

4. A protective devicev according to claim 2, wherein the means forsupporting the coil in radially spaced relation -to the liner membercomprises a Series of circumferentially-extending overlapping platesdisposed in annular assembly between the liner and the coil, the plateseach having a portion in contact wit-h the innermost layer of the coil,and each plate having circumferentially spaced edges and being lattachedat one of its circumferentially spaced edges to the liner member.

5. A protective arrangement according to claim 2, comprising also layersof sheet metal between the layers off the web.

6. A protective arrangement according to claim 2 wherein the web isformed from interwoven steel.

7. A protective arrangement according to claim 2, wherein the web isformed from interwoven drawn aluminum wires.

8. A protective device according to claim 4, wherein the tubular linermember has secured to it a series of axially-extending bars havingflanges which are radially spaced from the tubular liner member, therebeing one such axially-extending bar for each of the overlapping plates,the plates having each an inturned flange at one edge engaging below theflange on the corresponding axially-extending bar.

9. A protective device according to claim 8, one oi said overlappingplates having one end of the 'web attached to it.

10. A protective device according to claim 8, comprising a flan-ged -barsecured to one of said plates on the side thereof remote from thetubular liner member and having a flange radially spaced -from said oneof said plates, said web having at one end a hook ttinginterengagingwith the flange of the bar to attach the web to said one of said plates.e

1l. A protective device according to claim 2, said tubular liner memberand said outer tubular wall member forming an inner wall rand an outerwall respectively of a casing for the web, and comprising wall-formingmeans secured to the tubular liner member at axially spaced positions toform a pair of end walls of the casing and also to yform the means bywhichthe device is secured to the stationary structure, the tubularouter wall member being detachably connected with the end walls topermit its removal to expose the web. v

12. A protective device according to claim l1, said Wall-forming meanscomprising an axial -ange on one of said end walls, the outer tubularwall member slidingly engaging below said axial ange and having a radialflange abutting the other of said end walls, said other of the end wallsbein-g formed as a radial flange projecting radially from the tubularliner member.

13. A protective device according to claim 12, said stationary structureincluding a part defining an axiallyfacing channel, said means by whichthe device is supported from the stationary structure including anaxiallyextending part at the end of the tubular liner member remote fromsaid radial flange thereof, said axially-extending part being adaptedslidingly to engage said axiallyfacing channel, and retaining boltsengaging and securing together said radial flanges and the stationarystructure.

References Cited in the tile of this patent UNITED STATES PATENTS2,181,752 Warren Nov. 28, 1939 2,494,328 Bloomberg I an. l0, 19502,546,153 De Reiner Mar. 27, 1951 2,720,356 Erwin Oct. ll, v19552,802,618 Prachar Aug. 13, 1957 2,879,936 Faught Mar. 3l, 1959

